1. Technical Field of the Invention
The present invention relates to a terminal block for connecting electric wires.
2. Description of the Prior Art
It is known in the technical sector relating to the manufacture of switchboards for the wiring of electrical installations to use terminal blocks which are able to be mounted on associated supports and have opposite side openings for introducing in the longitudinal direction discontinuous wires to be connected electrically together by tightening a part movable in the direction transverse to the longitudinal direction of the wires.
Although fulfilling their function, these known terminal blocks nevertheless have drawbacks in particular with regard to certain applications such as connection of the output wires from a thermocouple which, as is known, are made of a different material and must be connected without creating a difference in potential which would give rise to an incorrect measurement read off the instrument situated remotely.
Particular types of terminal blocks designed for these applications are also known and essentially comprise:                two terminals forming the clamping part actuated by screws which can be operated externally and are joined to a small bar arranged between them and made of the same material as the wires to be connected together;        a single terminal into which the two opposite wires are inserted and clamped together by means of two screws which can be operated externally.        
In the first case this results in terminal blocks which are extremely precise, but which also have a high cost owing to the double terminals and the presence of the bars made of different material; in the second case the design is simplified, but at the cost of much less precision owing to the direct clamping action by means of screws.
In addition to this, the choice of materials and the dimensions of the connection (terminals plus screws) must be compatible with the material and the diameters of the wires to be connected, resulting in the need to produce and store a large number of different terminal blocks.